Where do the northern Atlantic salmon feed during their sea residence – in the Norwegian, Greenland or Barents Sea? (5.896Mb)

Where do the northern Atlantic salmon feed during their sea residence – in the Norwegian, Greenland or Barents Sea?

Martin-A. Svenning

Norwegian institute for nature research

Department of Arctic Ecology (NINA-Tromsø)

Co-authors:

Alexander Zubchenko & Sergei Prusov (PINRO-Murmansk, Russia)

Eero Niemelä & Jakko Erkinaro (Finnish Game and Fisheries Res. Inst.) Brian Dempson & Mike Power (DFO, Waterloo Univ.; Canada)

Reidar Borgstrøm (University of Life Sciences, Norway)

1-6 yr

Tana/Kola = 4-5 yr

1-5 yr

June/July 17 cm/30 g

Kelts

1 SW ~ ^{2 kg}

3 SW ~10 kg 5 SW ~25 kg

5000 10000

Total fangst (tonn)

1960 1965 1970 1975 1980 1985 1990 1995 Grønland Nord-Vest Nord-Øst Andre

Total capture (tons)

Greenland North-west North-east ”other”

1972 1982 1992 2002

YEAR 0

50000 100000 150000

Number of salmon captured

# sal m on captur ed

Tana, BZ Lista, Tuloma, Kola & Ponoi

2000

10 20 30 40

Elvefangster av Atlantisk laks (%) Andre

Canada Island Irland Skottland Russland Norge

?

River catches of Atlantic salmon

Norway Russia Scotland Ireland Iceland Canada Others

River catches (%)

Project rivers:

“Salmon in the North”: Phase I (2002-2006) and Phase II (2007-2010)

Temporal variation in abundance of the northernmost populations of Atlantic salmon with emphasis on the River Tana

Surveys, stable isotopes, satellites and salmon: exploring elements of the marine ecology of Barents Sea Salmo salar

(I) (II)

Norwegian institute for nature research (Co-ordinating institution)

Polar Research Institute of Marine Fisheries and Oceanography (Russia) Finnish Game and Fisheries Research Institute

University of Turko (Finland)

Department of Fisheries and Oceans (Canada) University of Waterloo (Canada)

University of Tromsø and Tromsø University Museum (Norway) University of Life Sciences (Norway)

Department of Environmental Affairs, County of Finnmark (Norway)

• present some “relevant” results from the two projects, i.e.:

• give a brief overview of the Barents sea salmon populations

• emphasize their uniqueness compared to other populations

• suggest/discuss/speculate possible feeding areas

• describe some activated projects (2007-10) to describe marine feeding areas

Angling – 40 % Commercial fisheries – 60 %

Year

1975 1980 1985 1990 1995 2000

Total catch (tonnes)

0 20 40 60 80 100 120 140 160 180 200 220 240 260

Estimated number of salmon in the catch

0 10000 20000 30000 40000 50000 60000 70000 80000 90000 100000 110000

1 SW 2 SW 3 SW 4-5 SW

Previous spawners

1 SW 2 SW 3 SW 4-5 SW TG

Tana: 1972-2006

(up to 20 % of catches in Europe)

Kola peninsula

• more than 65 rivers with Atlantic salmon

• fish traps in some rivers back to 1959

• rod and line fishery (catch and release) dominates

• fish trap in river Varzuga

• closing the river every second -> third day

• similar traps used in a few some Kola-rivers since 1959

• giving precise estimates of ascending salmon the last 45 years

• scale samples, SW, sizes, sea temperatures etc.

The kola peninsula rivers

– reliable information about ascending salmon since 1959

June July August

# o f sa lmon

Utsjoki/Tana

Varzuga

1SW MSW

June October

# of s alm on

Spawning next autumn !!

1-6 yr

Tana/Kola = 4-5 yr

1-5 yr

June/July

17 cm/30 g

Tana river

Utsjoki as an index river for Tana

RKTL (research station)

Video monitoring of descending smolts

and ascending adult salmon

Temporal and spatial migration patterns of Atlantic salmon salmon in

the sub-Arctic River Utsjoki – a large tributary to the Tana river

0.0 2.0 4.0 6.0 8.0 10.0 12.0 14.0 16.0

07-jun

14-jun

21-jun

28-jun

05-jul

12-jul

19-jul

26-jul Date

Frequency (%)

0 200 400 600 800 1000 1200 1400 1600 1800 2000

# smolt

Number of smolts descending Utsjoki per year

Totalt = 12 852 (2002) 13 800 (2003) 2002

12 852

2003 13 800

2004 27 113

Frequency (%)

2005 40 000

2006 26 000

• when entering the fjord/estuary?

• what about the other 30 tributaries?

0 % 5 % 10 % 15 % 20 % 25 % 30 % 35 % 40 % 45 %

0-25 26-50 51-75 76-100

Depth (%)

Fraction (%)

Less than 5 % of the smolts migrated in the upper 30 cm

When?

Where?

Both day (60 %) and night (40 %)

85%

Unique smolt behaviour for northern populations?

0 5 10 15 20 25 30 35

31.5.

7.6.

14.6.

21.6.

28.6.

5.7.

12.7.

19.7.

26.7.

2.8.

9.8.

16.8.

23.8.

30.8. Dato

Oppvandring/Fangst (%)

Oppgang 1SW (n=1203)

Oppgang 2SW og MSW (n=92) Fangst 1SW (n=104)

Fangst 2SW og MSW (n=31)

Ascendence and capture of adult salmon in Utsjoki

2SW/MSW

1SW

Date

No of salmon ascending/captured

By use of the video cameraes we may estimate the ”marine”

survival rate of the Utsjoki

salmon (annually)

Mortality for Atlantic salmon during the sea residence is probably density independent

Number of descending smolts

N umbe r of adult sa lmon re turning

Survival = 8 % (1976 – 1990)

Survival ≤ 3 % (after 1995)

Revised after Jonsson et al. 1998 (based on data from River Imsa)

Surv iv al ra te , Utsj oki (% )

2002 2003 2004 2005 2006 10

20

2002 12 852

2003 13 800

2004 27 113

No of smolts descending (Utsjoki)

2005 40 000

2006

25 000

1SW Multi SW

No of adults returning:

Survival rate in Utsjoki/Tana probably above 20 %

Survival rate; Yokonga (Kola) = 16 %

Higher ”marine” survial in northern populations?

Survival rate in

southern populations (last 10 yr)

Influence of ocean climate on Atlantic salmon?

Positively correlated to NAO-index

River Teno

100 200

300 River Näätämöjoki

Total catch (tonnes)

5 10 15 20

River Kola

20 40 60 80 100

Barents Sea

1975 1980 1985 1990 1995 2000

Temperature (°C)

3 4 5 6

Barents Sea

1975 1980 1985 1990 1995 2000

Temperature (°C)

3 4 5 6

1 SW

55 60 65

Teno Kola

Näätämöjoki

2 SW

Mean length (cm)

75 80 85 90 3 SW

95 100

4 SW

100 110 120

130 • correlated to the Kola section temperature

• not correlated to NAO-index

June July August

# o f sa lmon

Utsjoki/Tana

1SW MSW

Varzuga

June October

lengde (mm)

450 500 550 600 650 700

total antall ikter

1 10 100 1000 10000

summer salmon

autumn salmon

Different parasite burden suggest different marine feeding areas between summer and autumn salmon

Smolt age for most Tana and Kola

salmon ~ 4-5 years

Tana/Kola salmon – feeding where?

Age distribution of salmon smolts

captured in inner fjords and in ”open" sea

Smolt age

%

The low smolt age of postsmolt and adult salmon captured in the Norwegian Sea (2 yr) and inner ”southern” fjords (3 yr), strongly indicates that the Tana and Kola salmon are feeding elsewhere

– in the Barents Sea?

Recaptures of wild salmon tagged and released by the Faroes in the

autumn and in winter in the period 1992-95

Postsmolt trawling 1990-2001 (IMR)

Salmon smolt captured west of Novaya

Zemblya (Sept/Oct)

Pink salmon is very frequent along the Spitsbergen coast (even in lakes)

Adult Atlantic salmon captured annually in inner Isfjorden (LYR)

Commersial sea fishery for salmon in the

Neidenfjord up to 1974

Salmon in the north (2007-2010)

Surveys, stable isotopes, satellites and salmon:

exploring elements of the marine ecology of Barents Sea Salmo salar

Preliminary analyses of δ¹³C carbon and δ¹⁵N nitrogen isotope signatures of River Tana salmon, using scales sampled in the period 1992-2002

Assess long-term changes in the marine trophic ecology of salmon by analysis of stable isotope signatures of

carbon and nitrogen (δ13C and δ15N) in salmon scales sampled 1972-2007

• isotope signatures will be linked with salmon abundance, growth and also in relation to variation in marine climate conditions in the Barents Sea region

• analyses may provide an additional means to understand, in whole or in part, observed variability in abundance of various stocks of Atlantic salmon

• we hypothesize that nitrogen signatures would be higher during the second or third sea years owing to salmon feeding more piscivorously

1

We have also found a positive correlation between the size of adult salmon entering the Karasjokka river (a large tributary of river Tana) and the estimated density of capelin in the Barents Sea

Atlantic salmon (kelts) from the Tana river tagged with satellite (pop-up) tags in mid June 2007.

Determine marine distribution patterns and ocean forage areas across seasons by the combined use of archival

„pop-up‟ satellite tags and DST archival tags (tagging kelts)

• first time pop-up (satellite) tags have been used on salmon

• 25 Atlantic salmon kelts were tagged when descending Tana river (Jun 2007)

• tags are programmed to pop-up after 3 (Sep), 5, 7 and 9 months

• recording depth, temperature and “light” (dusk and dawn)

• also tagged with DST-tags in four rivers (measuring water temperatures)

2

Develop a time series of ”marine” survival of a northern European (Barents) Atlantic salmon stock (Utsjoki)

• continue the video monitoring in the Utsjoki river

• develop a time series of “marine” survival of a “Barents” salmon stock

• correlate survival rate with prey abundance, climate conditions etc.

3

Tana river

Utsjoki as an index river for a northern European (Barents) salmon stock

RKTL (research station)

Video monitoring of descending smolts and ascending adult salmon

Apply molecular genetic methods to identify individual stock components in a mixed-stock fishery

• obain more representative estimates of numbers of salmon that survive to return to home waters adjusting or correcting survival estimates to

account for in-river, and possibly coastal, fisheries

• i.e. to correct survival estimates obtained from video monitoring operations

4

Examine co-variation in abundance and survival of salmon stocks in different Barents Sea rivers

• influence of climate and climate variability on annual variation in survival and abundance of Barents Sea salmon stocks (including Målselv river)

• co-variation in abundance and changes in sea-age at maturity

5

Develop management plans for northern

Atlantic salmon rivers by integrating biological and local knowledge of the resource

6

Alexander

Zubchenko Sergei Prusov

Jaakko

Erkinaro Brian

Dempson Eero Niemelä

Reidar Borgstrøm Mike

Power

Thanks for your attention!